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YEP采用了先进的计算机管理技术与电子邮件网络系统,到目前为止,省项目办和英国DRA咨询专家与世界银行和涉及YEP的各有关单位之间及时准确地进行了大量的数据传输工作,保证了YEP工作的顺利进行。 相似文献
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Michael M. Reddy Kotra V. Krishnamurty Eugene Shpirt G. Anders Carlson Leo Hetling 《Environment international》1982,7(5):315-323
Total and particulate metal concentrations, measured during intensive synoptic studies of the Genesee River, NY, correlated with suspended-sediment concentration and river discharge. Dissolved metal concentrations, on the other hand, showed little systematic variation over the length of the river. Metal and sediment fluxes for two elevated-discharged periods peaked at a midbasin sampling site. For most metals at most sampling sties particulate materials comprised over one-half of the total material. Comparison of particulate material metal concentrations, normalized to the measured suspended-sediment concentrations had with basinwide average values shows that sites having low suspended-sediment concentrations had high particulate material metal contents relative to the basin averages, while sites with high suspended-sediment concentration had low metal contents. These results are consistent with a metal transport mechanism in the Genesee River involving (1) a nearly constant dissolved component, (2) a fine acid-soluble component, and (3) a coarse component that is effectively a neutral diluent in the sediment. Chemical factors, such as sediment organic content, also appear to affect metal transport in the Genesee River. 相似文献
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Castor canadensis ) management in Wyoming, USA, was sent to 5265 private-land managers and 124 public-land managers during 1993. The survey
was developed in response to increasing interest in beaver management and beaver reintroduction possibilities. Private-land
managers responding to the survey supplied information on 62,859 km2 of land area and 20,037 km of streams. Primary concerns about beaver damage centered on (in decreasing order of importance)
blocked irrigation ditches, girdled timber, blocked culverts, and flooded pastures, roads, crops, and timber. Primary benefits
that landowners perceive that beaver give them were, in order of importance, elevated water tables, increased riparian vegetation,
and increased stock-watering opportunities. Public-land managers also listed these benefits and detriments among their top
concerns for beaver. Over 45% of landowners with beaver on their property and all of the public-land managers displayed an
interest in a beaver reintroduction program and in more proactive beaver management. 相似文献
4.
In Finland, small forest lakes and rivers in the northern part of the country are more sensitive to acidic deposition than
other Finnish waters. In some lakes, acid-sensitive fish populations have declined. A nationwide survey of fishers showed
that, at present, the number of fishers whose primary fishing waters are affected by airborne acidification is negligible
compared to the estimated total number of adult fishers (1.1 million). The proportion of the fishers who mainly fish in water
types sensitive to airborne acidification is considerable, 3% for the rivers in northern Finland and 21% for small forest
lakes. There is general concern among fishers about the effects of acidification. Changes in the fishing waters are attributed
to acidification by 5–10% of the fishers, although in most cases other information about the fishing waters rules out acidification
as an explanation for the changes. Among those who fish in sensitive types of waters, a willingness to mitigate potential
damages was reported by approximately one third of all fishers. Clear differences in the willingness to rehabilitate the fishery
were observed in relation to the importance of fishing as a spare time activity and the distance between the fishing waters
and a home or summer cottage. 相似文献
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Environmental economists have long used surveys to gather information about people's preferences. A recent innovation in survey methodology has been the advent of web-based surveys. While the Internet appears to offer a promising alternative to conventional survey administration modes, concerns exist over potential sampling biases associated with web-based surveys and the effect these may have on valuation estimates. This paper compares results obtained from a travel cost questionnaire of visitors to Fraser Island, Australia, that was conducted using two alternate survey administration modes; conventional mail and web-based. It is found that response rates and the socio-demographic make-up of respondents to the two survey modes are not statistically different. Moreover, both modes yield similar consumer surplus estimates. 相似文献
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Socioeconomic, demographic, and attitudinal factors likely to influence individual initiative to use control measures against
gypsy moth infestation in New Hampshire are examined. Data were acquired through a mail survey from 629 individuals in three
targeted towns: Bow, Conway, and Exeter. Using logit regression analysis, numerous variables are shown to be statistically
significant in influencing an individual's willingness to use control measures. The influencing factors include: the individual
knowing the difference between the gypsy moth caterpillar and the eastern tent caterpillar; the individual being a homeowner
rather than a renter; the number of acres of land accompanying the individual's dwelling; the number of trees on the individual's
property; the individual's gender; and the individual's level of income. Aesthetic damage and the nuisance caused by gypsy
moth infestation were the primary reasons for individuals to use control measures. The results from this study indicate that
the motivation behind an individual's initiative to use control measures is influenced by diverse and varying factors. The
models, methodology, and results as applied and presented here are exploratory in nature, yet could prove informative for
researchers seeking a greater understanding of the interaction between humans and insect pests. 相似文献
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